Organizations increasingly rely on virtualization technologies to improve the flexibility, efficiency, and stability of their data centers. One aspect of virtualization involves provisioning virtual machines with virtual disks for data storage. Virtual disks, like physical disks, may have unallocated space (e.g., unformatted disk regions) and/or unused space (e.g., formatted but unused).
Due to the potentially large amounts of data required to store virtual disks, an organization may wish to maximize data storage performance while minimizing the cost of storage by using thin-provisioning solutions. In an effort to efficiently utilize available storage space, thin-provisioning solutions typically allocate storage space from a common pool to computing systems on an as-needed or just-in-time basis in an effort to prevent storage space from going to waste. Thin-provisioning solutions may also later reclaim previously allocated storage space when it is no longer in use and/or required.
Unfortunately, virtual disk files may continue to consume storage space in host file systems even when virtual volumes no longer utilize all of the corresponding virtual disk space. Traditional thin-provisioning solutions may therefore fail to reclaim unused storage space at the virtualized level. Accordingly, the instant disclosure identifies a need for systems and methods for reclaiming storage space from virtual machine disk images.